1. Field of the Invention
This invention relates generally to universal couplings and more particularly to universal joints and universal joint crosses.
2. Description of the Prior Art.
The prior art is replete with various forms and types of universal couplings in which internal passages have been provided for lubrication of their various operational parts. Additionally, such prior art universal joints have included additional mechanisms and devices which attempt to improve the lubrication effectiveness. For example, U.S. Pat. No. 3,070,980 to Slaght, patented Jan. 1, 1963, is representative of the prior art providing for an extremely complex bearing cap to enhance the lubricant flow to the needle bearings. U.S. Pat. No. 3,006,168 to Kayser, patented Oct. 31, 1961, also discloses a highly complex and expensive to manufacture self-lubricating universal joint having a multiplicity of parts which may fail during operation. U.S. Pat. No. 3,353,374 to Buthenhoff, patented Nov. 21, 1967, discloses a further example of a highly complex universal joint utilizing a plurality of moving seal and spring loaded devices. U.S. Pat. No. 3,470,711 to Kayser, patented Oct. 7, 1969, discloses yet another example of a highly complex universal joint and, more particularly, a cross therefor including a number of resilient members which may tend to distort and malfunction during operation. Other examples of representative prior art which attempted to solve the lubrication problem are as follows:
______________________________________ United States Pat. No. Patentee Patented ______________________________________ 1,889,470 F. A. Garrett November 29, 1932 1,968,787 W. W. Slaght et al July 31, 1934 1,992,257 H. F. Braun et al March 5, 1935 2,025,502 W. B. Fageol December 24, 1934 2,081,505 J. E. Padgett May 25, 1937 3,087,314 V. E. Jarvis et al April 30, 1963 3,178,907 J. M. Lyons April 20, 1965 3,242,695 P. M. Ross, Jr. March 29, 1966 3,352,127 R. L. Skinner, Sr. November 14, 1967 3,611,751 Hans-Joachim Kleinschmidt October 12, 1971 3,721,110 Borneman March 20, 1973 3,832,865 Lewis September 3, 1974 ______________________________________
The above-noted voluminous prior art patents all may be generally characterized as highly complex and generally vulnerable to malfunction and expensive to manufacture and none of such prior art devices includes effective means to ensure that each of the critical bearing areas are lubricated during each lubricating cycle. Further, they may be additionally characterized as difficult to maintain in the field, thus, potentially resulting in substantial downtime of the vehicle with which they are operationally associated.